THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

BARACK OBAMA, PRESIDENT OF THE UNITED STATES: Now's the time. It's a good time for all of to us reflect on how we treat each other and to insist on respect and equality for every human being. We have to end discrimination and violence against our brothers and sisters who are in the LGBT community, here at home and around the world, especially in countries where they are routinely prosecuted. We have to challenge the oppression of women, wherever it occurs, here or overseas.

[17:00:46] There's only us, Americans, here in Orlando; and the men and women taken from us, those who loved them. We see some of the true character of this country, the best of humanity coming roaring back. The love and the compassion and fierce resolve that will carry us through not just this atrocity but through whatever difficult times may confront us.

It's our pluralism and our respect for each other, including the young man who said to a friend he was super proud to be Latino. It's our love of country, the patriotism of an Army Reservist who was known as an amazing officer. It's our unity, the outpouring of love that so many across our country have shown to our fellow Americans who are LGBT, a display of solidarity that might have been unimaginable even a few years ago.

Out of this darkest of moments, that gives us hope. Seeing people reflect, seeing people's best instincts come out. Maybe in some cases, minds and hearts change.

It is our strength and our resilience. The same determination of a man who died here, who traveled the world, mindful of the risks as a gay man, but who spoke for all of us when he said, "You cannot be afraid. We are not going to be afraid." May we all find that same strength in our own lives. May we all find that same wisdom in how we treat one another.

May God bless all who we lost here in Orlando. May he comfort their families. May he heal the wounded. May he bring some solace to those whose hearts have been broken. May he give us resolve to do what's necessary to reduce the hatred of this world, to curb the violence; and may he watch over this country that we call home.

Thank you very much.

ANNOUNCER: This is CNN breaking news.

WOLF BLITZER, CNN ANCHOR: I'm Wolf Blitzer in THE SITUATION ROOM. Very, very strong words from the president of the United States. We're covering the breaking news. The president's very emotional statement about guns and violence just moments ago. Right now we just heard it, after visiting with survivors and families of the victims of the Orlando shootings.

Gloria, once again the president has had to become comforter in chief, meeting with all these families of the victims of this horrendous terror attack.

GLORIA BORGER, CNN CHIEF POLITICAL ANALYST: This isn't the first time we've seen the president in this -- in this role. And what was striking to me about his speech today was, yes, he spoke about ISIS and the notion of these lone-wolf attacks.

But he very early on in the speech turned to the question of politics and guns and said, "You know, we can't catch every single deranged person that wishes to do harm, but we can do something about the amount of damage that they do," and that politics makes it very easy for terrorists or a disturbed person to buy these kinds of powerful weapons.

So yet again, we heard the president talk about gun control and put this, really, very much in a political context as well as a -- as a foreign policy context.

BLITZER: Because he -- he definitely spoke about this was a lone-wolf attack, he said, Dana, "hatched in the mind of a disturbed person, a single killer with a powerful assault weapon." And then he spent a lot of time talking about the availability of guns in America.

DANA BASH, CNN CHIEF POLITICAL CORRESPONDENT: Right. That's right. And look, I mean, this happened the same day that the head of the CIA was on Capitol Hill, very bluntly saying that ISIS is still very much a threat in big cities, maybe even here. And that is very much on the minds of everybody.

But the fact is that, according to our colleagues' law enforcement sources, it's not entirely clear what the motive or string of motives that this killer had, whether he used ISIS as a -- you know, just kind of -- not an excuse, but he seized on ISIS as a way to funnel his frustrations and other issues that he might have been having.

But it is still a very real fear in this country. And as president of the United States, when you have somebody massacre almost 50 people, the biggest massacre on his watch in a line of horrific shootings, and they say something about ISIS, he's got to try to reassure the American people. And that's what he did. But there wasn't a big attempt at reassuring. It was an angry Obama

speech, saying we've got to -- "I'm sick of telling these families that I'm sorry; and I'm sick of having no answers when they come to me and say, 'Why does this keep happening?'"

JEFF ZELENY, CNN SENIOR WASHINGTON CORRESPONDENT: And when he said, "They don't care about the politics, and neither do I" after he was hugging families and things.

But the reality is, the politics are very important here. If the Senate, which was Democratically controlled at the time after Newtown, after that horrific shooting. At that point, we couldn't think of anything more brutal than a gunman walking into an elementary school. The Democrats controlled the Senate, and they could not get that passed. Vice President Biden made it his life's work every day up there.

Dana, you remember that as well as I.

BASH: Yes.

ZELENY: All of those intense debates. They couldn't do it.

BORGER: They lost Democrats.

ZELENY: They lost Democrats, of course. Now, the politics of this are changing, I do believe, on the Democratic side. And, you know, some Republicans were up this year. This is happening. Every year is an election year, but this is on the cusp of the presidential campaign. Donald Trump has been talking this week, Hillary Clinton talking. So it is a different moment.

But the president is saying it's going to require more than just her military. He is really calling on people, once again, to focus on this. But you're so right, Dana, about just on the day that this is happening, on the new threat of ISIS attacks here. Some people are going to ignore the gun control message here and go directly after the real threat. Republicans have been saying, John McCain, of course, will get into this, that the president, you know, deserves some blame for this.

BLITZER: And Michelle, you're over at the White House. The president also spent a lot of time talking about the discrimination against the LGBT community. The president was very, very strong in saying the discrimination and the violence here at home and around the world must end and must end right away. This was a very important part of his speech, as well.

KOSINSKI: Yes. He really lamented all of the terrible aspects of this, whether you look at the discrimination there, whether you look at the age of the victims, where they were, out for a night of fun. The president covered all of that and lamented all of that.

I don't think here, at least not in his speech, was he acting as comforter in chief. It sounded like he wanted to -- in the White House's view, wake America up. He even said that, if we don't choose to act and do more to stop certain people from getting easy access to guns, then we're actually choosing to let that happen.

And we know that the president has delivered this somewhat similar speech many times now. We've certainly seen him angrier; we've certainly seen him more emotional. We saw him start crying not too long ago when he talked about the Sandy Hook shooting.

Here he was more professorial. It was broad. He laid out his argument for why it's not just about going after ISIS militarily, why we need to go after lone wolves, why that includes preventing people who are simply disturbed or deranged from getting guns, and why the argument that adding more guns to the equation is, in his view, without common sense.

I think the most emotional point that spoke out, when he said once again, he held and hugged families who pleaded with him to do more, asked him why it keeps happening. That's when the president said, "They don't care about politics. Neither do I."

[17:10:09] He sounded less angry and less emotional in this speech than he sounded tired. Tired of it keeping happening. And he wanted to again lay out that broadest argument that he could for, in his view, why it doesn't make sense to keep not changing things.

BLITZER: Yes, he certainly was a comforter, though, to the families of the victims. He spent a lot of time with survivors, as well. No doubt he was trying to comfort them as best as he could.

This was happening as John McCain, the senator from Arizona, says that Barack Obama is to blame for the attack, telling reporters today -- let me read precisely what Senator McCain said -- "Barack Obama is directly responsible for it, because when he pulled everybody out of Iraq, al Qaeda went to Syria, became ISIS. And ISIS is what it is today thanks to Barack Obama's failures." Later he said he misspoke, and he tried to clarify that the policies were responsible.

Manu, you're up on the Hill. This has caused a huge uproar today, Senator McCain's comments.

MANU RAJU, CNN POLITICAL CORRESPONDENT: Yes, they did. It forced him to walk it back, but not completely, Wolf. As you noted, he said that the policies created this, not President -- the president was not directly responsible.

But I should note, in that gaggle with reporters this afternoon, McCain was blocked (ph), and he was a little agitated. He made it very clear that the president was directly responsible for what happened in Orlando. He was asked repeatedly, and he said, "Yes, the president is directly responsible." Those are very, very strong words.

But after it did cause that uproar, walking that back slightly. We should note John McCain in the middle of a very difficult re-election race. He has an August primary, something that he should be OK, should be safe in that primary. But he's wary of his challengers from the right but also has a very difficult race in the general election against Ann Kirkpatrick, a Democratic congresswoman. And clearly, Democrats are already jumping all over this, seeing this

as a vulnerability. But I should also note, McCain has been saying this before. Two days ago on the Senate floor, he also said that the policies were responsible for what happened in Orlando. Clearly some strong words from John McCain, not quite backing down, Wolf.

BLITZER: No. He said in his statement after the initial comments, he said, quote, "I misspoke. I did not mean to imply that the president was personally responsible. I was referring to President Obama's security decisions, not the president himself."

Manu, stand by. I want to get some more on all of this. Republican Senator James Langford of Oklahoma is joining us. He's a member of the Homeland Security and Intelligence Committees.

Senator, thanks very much for joining us. I want to get your immediate reaction to what we heard from Senator McCain, that the president, originally he said he was directly responsible, and then he later clarified.

Do you agree with Senator McCain?

SEN. JAMES LANGFORD (R), OKLAHOMA: Yes, he should have directly clarified that and said, "Obviously, the president is not directly responsible for that."

The problem the president has with what McCain said is it's very similar to what Brennan said today in the CIA hearing that we had, the open hearing. When I asked him personally about the lone-wolf attacks and what's happening in other regions, and asked him specifically about the caliphate in Syria and Iraq: how do we actually deal with this? Will we slow down these lone-wolf attacks, until we actually deal with that caliphate?

Brennan's response back is, "We have to deal with that caliphate? As long as that caliphate is there, and they continue to motivate people, they're going to continue to motivate these lone-wolf attacks around the world.

And so, well, obviously, the president is not personally responsible, and that's not the best way to be able to say that. As long as that caliphate is allowed to be able to stay there and we're not taking on them as an entity, they're going to continue to promulgate people. Whether it's at a Christmas party in California last year or whether it's in a nightclub in Orlando, they are going to continue to press and find local attacks.

BLITZER: Will you vote, Senator, in favor of the gun legislation that's coming up early next week, one that would prevent those on the terror watch list from getting a gun. The other would extend background checks for gun shows. How will you vote?

LANGFORD: Yes, I'm looking at all of those. The first principle for me is we have a Second Amendment, and we need to have whatever we pass be constitutional. Some of the challenges that are out there, they're trying to remove constitutional rights without actually going through due process. You can't do that. He couldn't say to one of these suspected terrorists, "You can no longer talk on the phone, no longer talk on the Internet, no longer go on a mosque," because those are protected constitutional rights.

We can't say, "Because you're a suspect, we take your phone away; you can't go on the Internet." You have to actually show something. You can't do that per the Second Amendment rights, as well.

And what I would want to reiterate to you, it's already the law right now. If someone is known or suspected as a terrorist, they cannot just walk in and buy a firearm. They have a long waiting period that actually kicks in that the system itself will kick them out. The FBI is pinged on that, and they get some options to be able to deal with it.

[17:15:08] So it is already current law. So there's a lot of pushback to say all these known terrorists can just walk in and buy a gun at a gun store. That is not correct. They are already held back and already cannot walk in and buy a gun in a gun store right now.

BLITZER: But they can go to these gun shows and buy guns without any background checks.

LANGFORD: Most of the people at a gun show are licensed dealers. I know you've been around gun shows...

BLITZER: Most are licensed, but there are some private -- private citizens that sell gun at gun shows.

LANGFORD: You're correct.

BLITZER: And there's no background checks that are required. A terrorist could walk go to a private citizen, buy them all, no background check, no nothing.

LANGFORD: That is correct, in the current system. But that's actually fairly rare, I would say, to say the least on it. We also asked the...

BLITZER: Shouldn't that loophole, Senator, be removed?

LANGFORD: Well, see, here's the challenge. If I buy a shotgun from my next-door neighbor, right now it's a one person selling to another person item on that.

What the gun show is, really, a group of individuals that are gathering together to be able to do those sales. By far, most of them are licensed dealers and most the individuals that are selling any king of high-powered rifle are also selling them through a dealer, where they'll actually go to a dealer, and so there'll be that background check.

So the problem is, you've got one individual selling to another a legal product, and that's the current system. It's a legal product on that. You're not going to go through and have every neighbor, if they're selling to a neighbor or selling to their grandson or selling to their uncle, to be able to have to go through all these background checks. That's not how we're set up. It is a legal product.

BLITZER: What if it's an AR-15? Would it be OK to purchase an AR-15 from a private individual without any background check?

LANGFORD: That is currently the law right now. It is.

BLITZER: Should it be changed? Should that law be changed?

LANGFORD: I don't think it should, actually. You're still in the same system. If I'm selling to a neighbor, if I'm selling to someone that I know, you're...

BLITZER: What if you're selling to someone you don't know?

LANGFORD: Well...

BLITZER: What if you're selling to someone you don't know, some individual? Some private individual walks into a gun show. You have no idea who this person is. He wants to buy an AR-15.

LANGFORD: I would say the vast majority of individuals that do that would actually go through a dealer, not through a private individual. So we're dealing with a problem.

I would say this is the same thing we dealt with with Jim Comey yesterday. Directly asked Jim Comey if we know of any individuals that are on the terror watch list that are trying to buy weapons. He could not think of a case where someone that is on that no-fly list is actually trying to buy a weapon, as well. So somewhat we're chasing down a solution to something that doesn't seem to be a problem at this point.

So the issue is, should that person be able to buy a weapon? No, they are a suspected terrorist. They should not be able to do that. But it's current law right now that that person cannot walk in and do that. The FBI is notified as soon as they are, and there's this long wait protection put into process before they could actually purchase that weapon.

BLITZER: Senator Langford, thanks very much for joining us.

LANGFORD: You bet.

BLITZER: Senator James Langford of Oklahoma.

The breaking news continues. We're also now learning the Orlando gunman was exchanging text messages with his wife during the three- hour massacre. We have details of what they said. That's next.

(COMMERCIAL BREAK)

[17:22:32] BLITZER: Breaking news in the Orlando massacre investigation. A law enforcement official is now telling CNN the gunman, Omar Mateen, exchanged text messages with his wife during his three-hour killing spree at the Pulse nightclub. He also searched for news of the attack on Facebook, posted his allegiance to ISIS and warned of more attacks in the United States.

CNN's chief national security correspondent, Jim Sciutto, is in Orlando, has new details on the investigation.

(BEGIN VIDEOTAPE)

OMAR MATEEN, PULSE NIGHTCLUB SHOOTER: No one gives a (EXPLETIVE DELETED). No one gives a (EXPLETIVE DELETED) here.

JIM SCIUTTO, CNN CHIEF NATIONAL SECURITY CORRESPONDENT: This is Orlando shooter Omar Mateen on duty as a security guard during the B.P. oil spill in the Gulf of Mexico. Matten was captured on hidden camera in a 2012 documentary on the spill, ranting about the people there to clean up the water.

MATEEN: Like, everybody is just out to get paid. They're, like, hoping for more oil to come out and more people to complain so they'll have the jobs.

SCIUTTO: Four years later, Mateen would carry out the worst mass shooting in modern American history. New video of the attack captured on a cell phone from inside the Pulse nightclub bathroom shows frightened club goers taking cover in a bathroom stall. One of the first police officers on the scene told CNN what he saw inside.

OFFICER OMAR DELGADO, EATONVILLE POLICE: It was kind of dark, you know, had the disco lights still going. And I just began yelling, "Hey, guys, come on out, come on out, come on out. You know, we've got you, we've got you." And just unfortunately, it took a minute but realized that they weren't faking it. They couldn't get up.

CHIEF JOHN MINA, ORLANDO POLICE: Our officers went in there, exchanged gunfire with him, forced him to retreat and basically become a barricade a gunman in the bathroom.

SCIUTTO: Police finally made the call to blow through a wall and into the club when Mateen made a threat to detonate bombs inside.

MINA: We had information that he was going to put explosive vests on four people and then blow the place up in 15 minutes. By that time, we were already set with our explosive breach, and that's when we made the decision.

SCIUTTO: In a letter to Facebook CEO Mark Zuckerberg, Senator Ron Johnson details the gunman searched on the social networking site for "Pulse Orlando" and "shooting" right in the middle of the rampage. Before and during the attack Mateen, the senator says, posted, quote, "Now taste the Islamic State vengeance."

[17:25:05] And one final chilling post, quote, "In the next few days, you will see attacks from the Islamic State in the USA." Investigators now continue to look at what Mateen's wife, Noor Salman,

knew about Mateen's plans. CNN has learned investigators believe she even communicated with her husband via text messages during his three- hour rampage.

Salman has now given conflicting statements, according to law enforcement officials, but admits that she suspected Mateen was planning an attack, possibly on Pulse. Salman has told investigators that, on the day before the shooting, she tried to tell Mateen not to commit an act of violence, but she did not call the police.

(END VIDEOTAPE)

BLITZER: Jim Sciutto reporting. Thank you, Jim.

Just days after President Obama said ISIS is losing ground, losing its leaders, losing morale, the director of the CIA today is painting a much darker picture. Director John Brennan testifying before Congress, saying ISIS is as dangerous as ever.

(BEGIN VIDEO CLIP)

JOHN BRENNAN, DIRECTOR OF THE CIA: Unfortunately, despite all our progress against ISIL on the battlefield and in the financial realm, our efforts have not reduced the group's terrorism capability and global reach.

In fact, as the pressure mounts on ISIL, we judge that it will intensify its global terror campaign to maintain its dominance of the global terrorism agenda. We judge that ISIL is training an attempting to deploy ISIL has a large western fighter who is could serve as operatives for attacks in the west. And the group is probably exploring a variety of means of infiltrating operatives into the west, including in refugee clothes, smuggling routes and legitimate methods of travel.

(END VIDEO CLIP)

BLITZER: Let's get some more now from the former head of the National Counterterrorism Center under both presidents, Bush and Obama. Michael Leiter is joining us. He's now with a national security company, Lidos. Michael, thank you very much for coming in.

MICHAEL LEITER, FORMER HEAD, NATIONAL COUNTERTERRORISM CENTER: Good to be here, Wolf.

BLITZER: Do you agree with that very dire assessment from the CIA director?

LEITER: I think I do. I think, although we're making some progress in Syria and Iraq, it's not enough. And even if you're disrupting them overseas.

The movement that has spawned, and the operatives have had, at least in western Europe, are really not being affected by that, and maybe driven even more as they see ISIS lose ground in the Middle East. BLITZER: Because clearly his words, the CIA director, were much more

ominous than what we heard earlier in the week from the president of the United States. How do you explain that?

LEITER: Well, I think they were and that comes from John Brennan being a really sober professional intelligence analyst who's been doing counterterrorism for many years.

You can push them in one place, in my view. We have to defeat them in Iraq and Syria. That is the head of the snack. But that doesn't stop these other elements to spread it out, whether it's in Libya, whether it's in western Europe or whether it's people who are not directed but are still inspired by ISIS here in the United States.

BLITZER: Is the president putting forward too rosy a picture?

LEITER: I wouldn't go that far. I think the president was speaking about the situation in Iraq and Syria. And again, I think we need to do more there.

The fact is, there's no single place that we have to defeat them. We have to defeat them in many places, and that is going to require multiple tools. I think the president was narrow in his description. I think John gave a more strategic view of what the threat really is.

BLITZER: And these words really impacted me because of the debate that you're hearing right now with Donald Trump, saying you've got to have a temporary ban on Muslim refugees coming into the United States.

When the CIA director says the group, referring to ISIS, is probably exploring a variety of means for infiltrating operatives into the west, including in refugee flows, smuggling routes and legitimate methods of travel. The legitimate methods of travel, if they have a European passport they could just come over for business or pleasure or tourism without any background check whatsoever.

LEITER: That's absolutely right. And the fact is, as a counterterrorism professional, You have to look out, and terrorists are going to use any path they can. This is really no different from al Qaeda. Al Qaeda used all of these methods and others to try to infiltrate the United States.

And in my view, there's no single way that you stop that either. You really do, again, require a multitude of tools: of screenings, screening people around western passports or a visa waiver; screaming, effectively, refugees. Doing the law enforcement here and intelligence here in the United States for people already here.

So it doesn't shock me that they are looking at all of these methods. And we can't turn this into a simplistic "there's one silver bullet that will solve all of it."

BLITZER: So when Trump says you just have a temporary ban, you don't agree with him on that?

LEITER: I -- not only do I disagree on it, it think it will be counterproductive from a terrorism perspective. Because it certainly feeds the narrative that ISIS is trying to spew already to find more.

BLITZER: What's your analysis of what happened at that nightclub in Orlando? Was this ISIS really at work, whether it was a direction from ISIS or simply an inspiration from ISIS? Was this ISIS at work?

LEITER: This is absolutely ISIS. And this question of direction versus inspiration that we've been so absorbed by, really, since al Qaeda and plots over the last 15 years, it's really less relevant for ISIS.

In many ways, we should be more worried about what happened in Orlando, which was no connection back to ISIS but inspiration by ISIS. Because simply that inspiration, without the communication, without the connectivity, makes it that much absorbed by al Qaeda and plots over the last 15 years, it's really less relevant for is.

[17:30:00] In many ways, we should be more worried about what happened in Orlando, which was no connection back to ISIS but inspiration by ISIS. Because simply that inspiration without the communication, without the connectivity, they took that much harder for law enforcement intelligence to detect and disrupt these plots.

BLITZER: If this is ISIS, how does the United States stop it?

LEITER: Well, as I've said, it requires every piece. It requires an offensive piece with military and special operations overseas. It requires deep engagement with European allies in the West. It requires law enforcement here in the United States and I think vastly more than what we've been doing today in terms of resources and potentially lowering the bar for investigations, and importantly it requires deep engagement with the Muslim communities.

The Muslim communities are harmed by this as much as anyone and the Muslim communities that know their own community. We partner with every community when we're trying to defeat other crime, gangs, we have to do exactly the same thing with Muslim communities here in western Europe.

BLITZER: You worked closely with the president but you were in the White House situation room when the killing of bin Laden took place. You know him well. When you hear Senator McCain say -- initially saying the president was directly responsible for what happened in Orlando then he clarified, he said I misspoke, I did not mean to imply the president was personally responsible, I was referring to President Obama's national security decisions, not the president himself.

But how much blame do you think the president has for what happened in Orlando?

LEITER: Well, I was lucky to work with President Obama. I've also been lucky to work with Senator McCain on several occasions. I think there are honest disagreements about what we have to do and I think -- Senator McCain's criticism of President Obama and the removal of troops from Iraq, I don't think there's any doubt the removal of troops from Iraq had allowed ISIS to do better. On the other hand, I don't think that is the only problem we have

here. I think it has to be addressed domestically, internationally, and I think in many ways President Obama, truthfully, was more aggressive in going after al Qaeda than was his predecessor with whom I also work, President Bush. So there are opposing cons on both sides of this balance. And what I hope we can do is move it away from Republican-Democrat, and back to national security priority.

BLITZER: More terrorists have been killed under President Obama than under President Bush. Is that what you're saying?

LEITER: That is certainly true in Pakistan. But it is also true during the last eight years. We have seen the emergence in the likes of ISIS in a way that we hadn't before. So again, there are opposing cons on both sides of this debate.

BLITZER: Good discussion. Michael Leiter, thanks very much for coming in.

LEITER: Good to be here, Wolf.

BLITZER: Coming up, the gunman described as verbally abusive, rude and aggressive in elementary school. We have new details of what may have been early warning signs. That's next.

(COMMERCIAL BREAK)

[17:35:04] BLITZER: We're following the breaking news in the Orlando terror investigation. Federal officials now say they have no record that backs up a gun store manager's claim he reported the killer's attempt to buy hardened body armor. We're learning of other warning signs going back several years.

CNN's Brian Todd is on the scene for us in Orlando. Brian, what else are you learning?

BRIAN TODD, CNN CORRESPONDENT: Wolf, tonight we have new accounts from former classmates and these documents that we have just obtained from the St. Lucie County School System showing a lifetime of red flags for Omar Mateen. But along the way, no one from the school system that he came up through to the FBI was able to put that mosaic together and stop Mateen's dangerous progression toward that night at the Pulse nightclub.

(BEGIN VIDEOTAPE)

TODD (voice-over): Alarming information tonight that his killer's pattern of disturbing behavior extended back to his childhood. Even as a young boy, Omar Mateen was troubled and disruptive.

A former classmate at Mariposa Elementary School in Port St. Lucie, Florida, tells CNN Mateen once threatened to bring a gun to school and kill everyone. That was in fourth or fifth grade. He was 9 or 10 years old. The classmate could not recall what punishment Mateen received but said it was, quote, "a very big deal at the time." Documents obtained by CNN from the St. Lucie County School show Mateen

was disciplined 31 times between 1992 and 1999. These school records described Mateen as, quote, "rude and aggressive," a note he talked frequently about violence and sex.

ROBERT ZIRKLE, RODE BUS WITH OMAR MATEEN: He was a little out there. Didn't really have too many friends.

TODD: Robert Zirkle rode the same bus route as Mateen during high school. Zirkle and other former classmates tells CNN in the days following September 11th, Mateen claimed Osama bin Laden was his uncle and made light of the attacks.

ZIRKLE: He was acting like a plane, like he had his arms out. He was like making a plane noise, and like he would -- he made like a boom sound or like an explosion type of sound, fell in his seat and was like laughing about it, like it was a joke or something. My friends and I were like, if you don't stop, man, it's going to be a problem.

TODD: As a teenage employee at Gold's Gym in Port St. Lucie, Omar Mateen was to be avoided.

STEFAN COMVALIUS, HELD TRAINING WITH OMAR MATEEN: He had that kind of aura that I don't think people really wanted to engage him because they don't know where they would go.

TODD: Stefan Comvalius held personal training sessions at Gold's Gym.

COMVALIUS: One of my clients, she was completing her set on the squat rack, and she, you know, was in full stride all the way down, and he made a derogatory statement about her anatomy, which, I mean, it was just completely unacceptable and loud at that. Like he wanted her to hear it.

TODD: Staff members at Gold's Gym could not recall any disciplinary issues with Mateen. A few years later, he was transferred from a job as a security guard at a courthouse after making inflammatory comments about terrorism. That's when the FBI started investigating him.

JAMES COMEY, FBI DIRECTOR: He said he hoped that law enforcement would raid his apartment and assault his wife and child so that he could martyr himself.

[17:40:03] TODD: Mateen's first wife said he verbally and physically abused her to the point that her family had to rescue her to get her out of the marriage.

SITORA YUSUFIY, OMAR MATEEN'S EX-WIFE: Emotional instability, sickness, mentally, he was mentally unstable and mentally ill. That's the only explanation that I can give. And he was obviously disturbed.

(END VIDEOTAPE)

TODD: Now these school records show that Omar Mateen repeatedly had interventions with school counselors, psychologists and others, but since the shootings his father has repeatedly said that he thought his son was normal -- Wolf.

BLITZER: Brian, was there a warning signal from a local gun shop owner some weeks before the massacre?

TODD: There was, Wolf. According to the gun store owner himself, this is -- the gentleman's name is Robert Abell. He is the owner of Lotus Gun Works in a nearby town Jensen Beach, he said that about six weeks ago after Mateen came in trying to buy level three body armor and a bulk ammunition and asked odd questions, that his staff became concerned and that they contacted authorities.

Now according to law enforcement officials, federal officials have no record of the Lotus Gun Works or any other store contacting them about Omar Mateen during that period and Martin County Sheriff's Office says the same thing. They don't have a record of it. The distinction could be in that they didn't just get a name associated with any call because the gun store owner does say that when they called authorities, they did not have a name Omar Mateen. They just reported his odd behavior.

BLITZER: All right, Brian Todd on the scene for us in Orlando, thank you for that report.

Joining us now here in THE SITUATION ROOM, CNN senior law enforcement analyst, the former FBI assistant director Tom Fuentes, Shadi Hamid of the Brookings Institution Center for Middle East Policy, he's the author of the book, "Islamic Exceptionalism; How the Struggle Over Islam is Reshaping the World." Also with us our justice correspondent Evan Perez and CNN counterterrorism terrorism analyst, the former CIA official, Phil Mudd.

Evan, what are you learning about the communication that apparently took place during that three-hour massacre between the terrorist and his wife?

EVAN PEREZ, CNN JUSTICE CORRESPONDENT: Somewhere around 4:00 a.m., Wolf, about two hours after this massacre began, it appears that he began exchanging text messages with his wife. Now we don't know at this point whether she knew what exactly was happening. He said, are you -- have you seen the news? At some point she becomes aware and she knows that there's a massacre and she suspects that her husband is behind it, and she starts frantically making these phone calls. He does not pick up.

Now that's also part of the picture that the FBI is still trying to put together of exactly what she knew when she knew it because, as you know, there's an investigation focused on that.

BLITZER: In the months leading up to this, Phil Mudd, there were apparently efforts by this terrorist to go online, to search information about the San Bernardino terrorist, to search information about Abu Bakr al-Baghdadi, the head of ISIS. How hard is it for the FBI, for example, to monitor suspected social media activity?

PHIL MUDD, CNN COUNTERTERRORISM ANALYST: Well, I wouldn't say it's hard. I'd say it's impossible. One of the keys you want to look at in this case, Wolf, is whether he's interacting with somebody, especially an FBI informant, and it indicates something about an interest in violence. In this case, searching about San Bernardino, there's got to be tens of millions of Americans who've done that.

The other thing you've got to remember, when the FBI was investigating him, let's look at our timeline, 2013, 2014. San Bernardino happened in December of 2015 after the case was closed. So the FBI isn't even looking at this guy anymore. I think the chance they could have picked up on these signals is zero simply because they weren't investigating him anymore and they are not searching through the tens of millions of Americans who are simply showing an interest in the San Bernardino killings.

BLITZER: What kind of role, Tom, should like companies like Facebook or Twitter for that matter play in helping law enforcement if they suspect something is wrong?

TOM FUENTES, CNN LAW ENFORCEMENT ANALYST: Well, the problem is to get them to suspect in the first place, Wolf, and I think Phil is exactly right. Tens of millions of people search those sites after the incident. I searched personally for information about San Bernardino and al-Baghdadi and ISIS and what's going on in every one of these attacks. We all do that as investigators and reporters look at what happened to try to get information from other sources online. So that's impossible for the bureau to sort that out.

As far as Facebook and the social media, I think it depends how closely they are actually looking at the messaging. They are looking at the system and how many people are online and how many use their service but for them to actually look at all content all the time, I think that's going to -- very easy in retrospect.

PEREZ: But keep in mind, keep in mind, these companies do a very good job in moving copyrighted, for instance. They have ways, they have computers that can analyze them and just, you know, pick up on key words. I mean, I'm not saying that certainly people's First Amendment rights need to restricted, but there is more, it seems like, some of these companies could be doing to flag some of this stuff.

BLITZER: Shadi, it's been several days now since the attack at that nightclub. ISIS originally, you know, claimed responsibility but they have been relatively silent since then, haven't they?

[17:45:07] What has been their reaction? I'm wondering because there's been a lot of reporting out there that perhaps this terrorist himself was gay.

SHADI HAMID, BROOKINGS INSTITUTION CENTER FOR MIDDLE EAST POLICY: Yes. So I think first of all this was an ISIS-inspired attack. So ISIS central does not seem to have been involved and this is in the new scary era that we're in. Someone can -- want to commit a terrorist act and then pledge allegiance to a group like ISIS at the very last minute and then invest their act with more meaning and that's exactly what's happened. In that sense, ISIS has gained from this because we are now having a national debate in a way that we wouldn't have been if it were just some regular shooter, right? So that's one thing. In terms of his sexuality some people might say,

well, would ISIS really want to have the allegiance of someone who might have been guy? I actually think they don't -- they wouldn't have a big problem with that, and in some sense it might preferable in that here's someone who actually tried to redeem himself, redeem his, quote-unquote, sinfulness through an act of violence. And this is what we've seen with a lot of terrorists in the West. They are actually -- quote-unquote, sinful or not pious or not very observant before they commit their act and then there seems to be almost an aspect of guilt and then they are trying to redeem themselves to an act of martyrdom. So I think that's the best -- that's the way we can better understand this.

BLITZER: So he was trying to repent in other words.

HAMID: In a way, yes.

BLITZER: They would interpret it like that so they might not walk away.

All right, guys. Stand by. There's more coming up.

Also, Donald Trump celebrates the anniversary of his entering the race for president but some worried Republicans still are looking for a way to replace him at the top of the ticket.

(COMMERCIAL BREAK)

[17:51:27] BLITZER: We have much more to come on the breaking news in the Orlando terror attack investigation. We are also standing by for a Donald Trump rally in Dallas, Texas, where he will be marking today's anniversary of his presidential campaign.

Just a little while ago Trump put out a written statement saying, and I am quoting now, "While I am thankful for the phenomenal success we have enjoyed in the past year, it is just the beginning."

CNN political reporter Sara Murray is on the scene for us in Dallas.

Sara, the statement makes no mention of the Republican establishment's growing doubts about Trump. What's the latest?

SARA MURRAY, CNN POLITICS CORRESPONDENT: Yes. Imagine that, Wolf. And that's not even the only backlash Donald Trump is facing today. He spent the morning in Washington, D.C. being deposed in a case. This is where one of the chefs pulled out of his D.C. hotel that he's building in protest of the comments Donald Trump has made about Mexicans. In response, Donald Trump is suing that chef. So in addition to navigating all of these issues dealing with his business, he's also trying to navigate the alarm that we're hearing from members of Trump's own party about his candidacy.

(BEGIN VIDEOTAPE)

MURRAY (voice-over): After a year as the ultimate outsider, Donald Trump says he is happy to stick with his go-it-alone strategy. DONALD TRUMP (R), PRESUMPTIVE PRESIDENTIAL NOMINEE: We have to have

our Republicans either stick together or let me just do it by myself.

MURRAY: And following a string of firestorms, Trump just might have to. From criticizing a federal judge.

TRUMP: I have a judge who is a hater of Donald Trump.

MURRAY: To suggesting the president sympathizes with terrorists.

TRUMP: We are led by a man that either is not tough, not smart or he's got something else in mind.

MURRAY: To doubling down on his Muslim ban.

TRUMP: But we have to stop people from pouring into our country. We have to stop it. Until we find out what the hell is going on.

MURRAY: It has driven some Republicans to quietly discuss extraordinary options, however farfetched, even talk of orchestrating a convention coup before Trump is officially anointed in Cleveland.

Among the ideas on the table, finding a way to free delegates through a new convention rule or so-called conscience clause, to allow them to vote for whoever they prefer rather than be bound by the will of the voters. And Trump offers this advice to GOP critics.

TRUMP: Just please be quiet, don't talk.

MURRAY: House Speaker Paul Ryan's response to those comments today?

REP. PAUL RYAN (R), HOUSE SPEAKER: You can't make this up sometimes. I'll just say, we represent a separate but equal branch of government.

MURRAY: But Ryan says he still plans to support the presumptive nominee.

UNIDENTIFIED MALE: Do you envision any scenario in which you would rescind your endorsement?

RYAN: That's not my plan. I don't have a plan to do that. Look, we're going to agree to disagree on some things.

MURRAY: With the GOP in turmoil, Hillary Clinton is making early moves to define her opponent as a divisive bully.

TRUMP: Knock the crap out of him, would you? Seriously.

MURRAY: All while painting herself in a positive light.

UNIDENTIFIED MALE: But for Hillary, one thing never changed. Helping children has been a cause of her life.

MURRAY: Airing ads like this one across eight battleground states.

(END VIDEOTAPE)

MURRAY: Now we're expecting Donald Trump here in Dallas in just a couple of hours. Of course the deep red state of Texas is not a traditional battleground state in November but it is a cash cow for GOP politics and Trump is holding a fundraiser here today, as well as two other fundraisers in Texas tomorrow.

[17:55:07] A source tells me they expect to raise north of $6 million in all of those three events combined. That could be a big help to the Trump campaign at a time when they are struggling to catch up with Hillary Clinton in the money race ahead of the general election -- Wolf.

Coming up, we have the chilling text messages between the Orlando gunman and his wife. We're learning what they were saying to each other during that three-hour killing spree.

(COMMERCIAL BREAK)

BLITZER: Happening now. Breaking news. The killer's words. We are hearing the Orlando attacker's voice for the first time and learning more about his final messages including texts with his wife and threatening Facebook posts during the massacre.